24 THE GROUSE SUBFAMILY 



the "winter-summer" plumage of Mr. Ogilvie- Grant than in the 

 case of the two plumages of the mallard. 



Objections may be raised to this interpretation, but nevertheless, 

 when the facts are squarely faced, it will be found that such objections 

 are groundless. The facts alluded to are as follows : In a large 

 number of species both adults and young wear a similar and dull- 

 coloured dress throughout the year. In a considerable, but smaller, 

 number of species both sexes, and the young, are similarly but 

 brightly hued. Between these extremes are many gradations, 

 permutations, and combinations. But we may put it, in a general 

 way, that the first to develop resplendent plumage is the adult male, 

 and then as a "breeding" or "nuptial" dress, to be speedily replaced 

 by one of more sober coloration, e.g. ruff (Machetes (Pavoncella) 

 pugnax). The female and young in such cases retain the ancestral 

 livery. Later the adult female assumes the dress of the male, leaving 

 the ancestral dress to the young. The blackcock and the partridge * 

 indicate the manner in which the earlier ancestral livery is gradually 

 eliminated, and the "nuptial" dress from a seasonal, becomes a 

 permanent livery. 



This condensed epitome of plumage evolution may help, it is 

 hoped, to bring the puzzling anomalies of the red-grouse liveries into 

 line with what obtains in the matter of plumage sequences elsewhere. 

 Regarded in this light, then, the plumage of the male red-grouse, 

 which is assumed at the end of the autumn, answers to that of the 

 mallard assumed at the beginning thereof, and in both cases it is 

 worn after the breeding season. The mallard, at this time, goes into 

 "eclipse," that is to say, he exchanges his bright livery for one of 

 more sober hues, and closely resembling that of the female. The 

 red-grouse at the same season assumes what is generally called an 

 " autumn " dress, adopting the nomenclature of Mr. Ogilvie-Grant. It 



1 That the interpretation of " eclipse" plumages here given is well founded is shown by the 

 fact that in the partridge, wherein both sexes are coloured alike, the male and female undergo a 

 similar phase of "eclipse"; this is what we should expect if the premises of this argument 

 have any solid foundation. 



